There are available on the market today heat pumps which utilize a compressed refrigerant and can be combined with domestic water heating. These systems operate in either a refrigerant desuperheating or condensing mode to provide hot water while simultaneously providing space heating or cooling. Additionally these systems provide hot water in a refrigerant condensing mode when no space cooling or space heating is required. The cost for these types of devices is high and puts them out of the reach of average consumers. Furthermore the complexity of such systems is beyond the comprehension of most of the local HVAC contractors and therefore makes their installation expensive.
In contrast, relatively inexpensive systems or field added components provide for the integration of water heating by desuperheating refrigerant while the system is cooling a space or heating a space and the heat pump has excessive heating capacity. This type of system is much less expensive and less complex than the first system described. However, it only provides domestic water heating if there is a simultaneous cooling or heating demand from the conditioned space.